My dear son of Diti, with your great determination and austerity you have done what was impossible even for great saintly persons, and thus I have certainly been conquered by you.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
व्यवसायेन तेऽनेन दुष्करेण मनस्विनाम् । तपोनिष्ठेन भवता जितोऽहं दितिनन्दन
vyavasāyena te'nena duṣkareṇa manasvinām | taponiṣṭhena bhavatā jito'haṃ ditinandana
SB 7.3.20